During the semiconductor patterning process it is common for micro-bridging defects to occur. It is particularly common for micro-bridging defects to form in the resist patterns after the lithography process in advanced technology nodes, for example, nodes of approximately 32 nm and beyond. Micro-bridging defects include small connections between two adjacent lines in a photo-resist pattern, which may cross-link two or more resist patterns in close proximity leading to the creation of single-line opens after etching. The cross-linking of the resist patterns of micro-bridging defects may cause a serious decrease in the production yield of advanced integrated circuits.
Existing solutions for removing micro-bridging defects include increasing the dose of exposure to the wafer during the lithography process step. However, this method of removing micro-bridging defects requires changing the develop critical dimension (DCD) target, in addition, a new optical proximity correction (OPC) module is needed to address the DCD retargeting. An alternative existing solution includes using a “better” photo-resist material to prevent the micro-bridging defects. The “better” resist would have extraordinary image contrast. After exposure and develop, the edge of resist pattern would be clean and no line-edge roughness. However, this method of removing the micro-bridging defects requires an “ideal” photo-resist, which is not yet available.
Accordingly, a need exists for a process of removing micro-bridging defects after the lithography process during fabrication.